The present invention relates to a data storage device test method to check if an assembled data storage device operates normally, and a data storage device manufacture method which has a test stage to check if an assembled data storage device operates normally.
Generally, after assembly, a hard disk device (HDD) undergoes various test stages such as servo write, a function test, burn-in and a final test before shipped. For mass production of HDDs, it is preferable to be able to test (inspect) a large number of assembled HDDs in a short period of time without occupying a large space. If testers are connected to HDDs on a one for one basis, it is not possible to reduce the occupied space since as many testers as HDDs are needed to test the HDDs at a time.
In order to reduce the occupied space, it is preferable to test many HDDs as quickly as possible by one tester. Accordingly, Patent Document 1 (Japanese Patent Laid-open No. 10-64173) discloses a burn-in test method in which many HDDs under test are connected to one host computer.
In the case of the test method described in Patent Document 1, one host computer is connected to twenty test computers each of which has three dual-channel IDE (Integrated Device Electronics) adapters attached thereto. Two HDDs under test are connected to each IDE adapter. The HDDs under test, which are connected to the IDE adapters, are accommodated in a high temperature burn-in chamber while the test computers are accommodated in a control chamber. This method tests plural HDDs at a time while lowering the failure rate of the test computers since the test computers are accommodated in a room temperature chamber and not in a high temperature chamber.
The existing IDE (ATA (AT Attachment)) interface can have a maximum of four devices connected thereto. A mother board supporting the IDE interface has two IDE ports. One is called Primary while the other Secondary. To each IDE port, two IDE devices can be connected. One is called Master while the other Slave. Each device to be connected has a jumper switch by which the device is set as Master or Slave. The highest priority is given to Primary Master, followed by Primary Slave, Secondary Master and Secondary Slave in this order.
Thus, a maximum of four HDDs can be tested per tester. In a typical HDD manufacturing test, HDDs are tested by making them execute many commands. For each command, a process composed of command issuance, data transfer (when needed to process the command) and drive status confirmation is executed as a unit of test. In the case of testing four HDDs by one tester, command issuance, data transfer and status verification are done as a unit of test with the four HDDs by turns.
To test two HDDs connected to an IDE adapter connected to a test computer by the method described in Patent Document 1, the above-mentioned command issuance through status confirmation process must be done for each command as a unit of test with the two HDDs in turn. That is, although plural HDDs are connected to one test computer, the test computer issues one command to only one HDD at a time. Therefore, the test time may be long although the occupied space can be reduced as compared with a one-for-one configuration which connects one test computer to each HDD.
On the other hand, each HDD may execute one of a number of different activity sequences to process a command depending on whether an error occurs. It is therefore feasible for a test computer to issue the same command to, for example, two HDDs at the same time. If one HDD does not execute an operation as required, testing of the other HDD may continue to be impossible while the failed HDD is inspected by another command, resulting in making the test time longer on the contrary.